Agents suitable for improving lubricants



Penman. 26, 1944 AGENTS SUITABLE FOR. IMPROVING LUBRICANTS Robert Ulothand Martin Mueller-Cunradi, Ludwigshafen-on-the-Rhine, Germany; vestedin the Alien Property Custodian No Drawing. Application April 28, 1939,Serial No. 270,650. In Germany January 29, 1935 12 Claims.

The present invention relates to new agents suitable for the improvementof lubricants, more particularly of lubricating oils, and to a methodfor producing these agents.

We have found that improving agents for lubricants of highefliciency areobtained by acting on fatty acids which contain one or more doublelinkages and/or hydroxyl groups, or on esters of the said fatty acids,more particularly their glycerides, as for example drying or semi-dryinganimal or vegetable oils, with boron halides at temperatures of at least50 C. and, if so desired, decomposing the resulting thickened oils withselective solvents. By adding the products thus obtained to lubricants,more particularly to lubricating oils, they improve the properties ofthe latter, for example by raising the viscosity, improving thetemperaturewiscosity curves, lowermg the pour point, reducing theformation of sludge and diminishing the tendency to form pitch.

Among the drying or semi-drying vegetable oils soy bean oil, cottonseedoil, castor oil, rape oil and linseed oil and among the animal oilswhale oil and neats-foot oil may be mentioned, by way of example, asstarting materials, The fatty acids contained in the said oils, as wellas synthetic acids and acid esters having a similar nature may also beemployed as starting materials. It is preferred to employ as initialmaterials such fatty oils as are known. to belong to the class ofnon-drying or semi-drying oils (cf. Holde, Kohlenwasserstoffole undFette, 6th ed., page 598 et seq.) Or the fatty acids which are found inoils of the said classes.

The initial materials may be polymerized in an undiluted condition oralso in admixture with diluents or solvents, as for example benzine,illu-' minating oil or carbon tetrachloride. Among the boron halidesboron fluoride which may be used in the gaseous state or in the form ofits addition or complex compounds, for example with glacial acetic acidor'with ethers, or also in admixture with suitable solvents, as forexample nitrobenzene or phenol, is particularly'suitable. The treatmentis performed at a temperatureof at least 50 C., but preferably at ahigher temperature which, however, as a rule should not exceed 160 C.,the boron fluoride for example being slowly passed in the gaseous stateinto the oil, while stirring, until the necessary amount has beenabsorbed.

The resulting products, when added to lubricants, for examplelubricating oils, improve the temperature-viscosity curve and increasethe viscosity thereof. They also often possess the property of loweringthe pour point of lubricating oils, which undesirably high pour point isusually caused by the presence of parafiln wax in said oils, but forthis purpose it is often necessary to add the polymerization products inlarge amounts and under certain circumstances no lowering of the pourpoint may take place at all. However, it is often undesirable to add tothe lubricating oils large amounts of products containing oxygen,because other undesirable properties may be thereby imparted to theoils.

We have further found that the polymerization products obtained asaforedescribed may be improved by treating them with selective solvents,whereby two fractions are obtained, one of which has a high molecularweight and a high emciency for lowering the pour point, while the otherhaving a lower molecular weight has only slight activity in thisrespect. The emciency of the high molecular portion depends on theselective dissolving power of the solvent applied, on its amount, on thetemperature and kind of the treatment. As suitable selective solventsfor this purpose we may mention by way of example alcohols, ketones,phenols, esters, aldehydes, chlorhydrins, ethers and chlorinated ethers,compounds containing nitrogen, as for example nitrobenzene, aniline andnitriles, also liquid sulphurous acid, hydrocarbons having a low boilingpoint, as for example propane. and butane, or

preferably mixtures of several selective solvents.

The high molecular fractions of the polymerization products have aconsistency ranging from viscous to plastic and a from yellow to browncolor. They are usually dificultly soluble or insoluble in the saidselective solvents. For the improvement of their color they may betreated with bleaching earths. On the other hand, their molecular weightmay be increased still further by subjecting them to another treatmentwith selective solvents or with boron fluoride.

When adding the said high molecular fractions of the polymerizationproducts to lubricating oils by fractions of one per cent or by a fewper cent, they are capable of lowering the pour point thereofconsiderably. The degree of lowering of the pour point depends on theinitial oil, on the method of preparation and on the nature of thelubricating oil to be improved. Another beneficial action of theadditions on lubricating oils resides in their capacity of rendering theoils more stable to oxidation which in turn results for example in areduced tendency towards the formation of asphalts.

The fractions soluble in theselective Solvents either are unchangedinitial materials or oils having undergone only slight polymerization;they maybe treated anew with boron fluoride and thus converted'into highmolecular products of high efficiency.

The following examples serve to illustrate how the present inventionmaybe carried out in practice, but the invention is not restrictedthereto.

Example 1 Soy bean oil having a viscosity of 1.72 E. at 99 C. is heatedto 130 C. 'in a stirring vessel and 2.3 per cent by weight of boronfluoride are led in within 30 minutes, stirring being then continued foradditional 30 minutes at 130 C. After removing the boron fluoride bywashing out with water or an alcoholic solution of caustic alkai, aproduct is obtained which has a viscosity of 9.5 E. at 100 C. and whichon addition in an amount of 20 per cent by weight lowers the pour pointof a lubricating oil (having a specific gravity of 0.906 at 20 C. and aviscosity of 1.85 E. at 99 C.) from 8 to -17 C.

By extracting the polymerization product at 80 C. with 2 parts by weightof amyl alcohol an insoluble residue results which, when added in anamount of 2 per cent by weight, lowers the pour point of the saidlubricating oil to -28 C.

Example 2 4 per cent by weight of boron fluoride are led at 130 C.within 6 hours into cottonseed oil having a viscosity of 1.8 E. at 99 C.The reaction product is diluted with benzine and washed with water untilneutral. After distilling off the solvent, a plastic mass is obtainedwhich has a viscosity of 17.8 E. at 99 C. By adding per cent by weightof the said product to the same lubrieating oil as described in Example1 the pour point thereof is lowered to 28 C.

After extracting the polymerization product by means of 3 parts byvolume of amyl alcohol, 2 per cent by weight of the fraction insolublein the amyl alcohol lower the pour point of the lubricating oil to 27C.; after repeating the extraction 1 per cent and 0.5 per cent byweight, respectively, of the insoluble fraction lower the pour point ofthe lubricating oil to --33 and to 32 C., respectively.

This application is a continuation in part of our copending applicationSer. No. 60,638 filed January 24, 1936.

What we claim is:

1. A composition of matter essentially comprising a lubricating oilhaving an undesirably high pour point and a polymerization product whichhas been obtained by treating soy bean oil at a temperature of about 130C. for about one hour with about 2.8% by weight of boron fluoride untilthat amount of boron fluoride has been absorbed which is necessary toproduce polymers which are soluble in said lubricating oil and capableof materially depressing the pour point oi that lubricating oil whendissolved therein.

2. A composition of matter essentially comprising a lubricating. oilhaving an undesirably high pour point and a polymerization product whichhas been obtained by treating cotton seed oil at a temperature of aboutC. for about 6 hours with about 4% by weight of boron fluoride untilthat amount of boron fluoride has been absorbed which is necessary toproduce polymers which are soluble in said lubricating oil and capableof materially depressing the pour point of that lubricating oil whendissolved therein.

3. A composition as claimed in claim 1 in which the polymerizationproduct prior to being incorporated with the lubricating oil has beentreated with a selective solvent to recover a highmolecular fraction ofsaid product.

4. A composition as claimed in claim 1 in which the undesirably highpour point of the lubricating oil is due to the presence of paraflinwax.

5. A composition as claimed in claim 1 in which the polymerizationproduct is present in a minor proportion, as compared with thelubrieating oil. v

6. A composition as claimed in claim 1 in which the polymerizationproduct is present in an amount not exceeding 5 per cent.

7. A composition as claimed in claim 1 in which the polymerizationproduct has been obtained by carrying out the treatment with boronfluoride in the presence of a diluent selected from the group consistingof benzine, illuminating oil an carbon tetrachloride.

8. A composition as claimed in claim 2 in which the polymerizationproduct prior to being incorporated with the lubricating oil has beentreated with a selective solvent to recover a high-molecular fraction ofsaid product.

9. A composition as claimed in claim 2 in which the undesirably highpour point of the lubricating oil is due to the presence of paraflinwax.

10. A composition as claimed in claim 2 in which the polymerizationproduct is present in a minor proportion, as compared with thelubricating oil.

11. A composition as claimed in claim 2 in which the polymerizationproduct is present in an amount not exceeding 5 per cent.

12. A composition as claimed in claim 2 in which the polymerizationproduct has been obtained by carrying out the treatment with boronfluoride in the presence of a diluent selected from the group consistingof benzine, illuminating oil and carbon tetrachloride.

ROBERT ULOTH. MARTIN MUELLER-CUNRADI.

